Purpose :
In clinical practice, dosing regimens for neovascular age-related macular degeneration (nAMD) are often guided by assumptions based on a patient’s prior treatment response. The purpose of this analysis was to determine if the duration of response to previous treatment with ranibizumab (RBZ) predicts future disease activity and need for subsequent injections in patients with subfoveal nAMD.

Methods :
In this retrospective, subgroup analysis of the phase III HARBOR study, treatment patterns associated with RBZ 0.5 mg PRN dosing were examined over 24 months. A “quiescent event” was defined as a period in months when an intravitreal injection was not required because the patient did not meet retreatment criteria (ie, they did not exhibit any neovascular activity on SD-OCT or a ≥5-letter decrease in BCVA from the previous visit). The percentage of eyes that were quiescent at the next month after a first quiescent event was evaluated. Additionally, the duration of time that eyes remained quiescent after the quiescent events of 2-6 months was evaluated by Kaplan-Meier estimates.

Results :
In total, 217 patients in the RBZ 0.5 mg PRN group received 3 loading doses and had ≤1 missing study visit, which was imputed as not having received an injection. The percentage of eyes that were quiescent at the next month after a quiescent event of two, three, four, five and six consecutive months without an injection was 40% (61/151), 67% (67/100), 74% (57/77), 64% (42/66), and 81% (39/48), respectively. The percentage of eyes that were still quiescent at the next two months after a quiescent event of two, three, four, five and six months was 27% (40/149), 47% (47/100), 47% (35/75), 53% (34/64) and 57% (26/46), respectively. After quiescent events of two, three, four, five, and six consecutive months, the mean (SEM) additional consecutive time quiescent was 1.25 (0.17), 2.44 (0.33), 2.94 (0.44), 3.19 (0.50), and 3.97 (0.60) months, respectively.

Conclusions :
PRN dosing with RBZ 0.5 mg can likely be modified based on a patient’s individual response to prior treatment. Longer periods of disease quiescence may predict longer disease-free intervals; however, the association varies among patients. Therefore, while longer intervals suggest greater likelihood of not needing an injection within 1-2 months, regular assessment of patients is warranted due to the unpredictable nature of nAMD disease activity.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.